Machine for making vacuum tubes



' Oct. 8, 1929. c, FITCH 1,730,926

CHINE FOR IAKING VACUUM ,NJBES Original" Filed Oct. 30, 1925 3 Sheets-Sheet l Oct. 8, 1929. c. s. FITCH MACHINE FOR IAKING VACUUI TUBES Original Filed Oct. 30, 1925 3 Sheets-Sheet 2 Oct, 8 19290 c, E, F T 1,730,926

MACHINE FOR BAKING VACUUM TUBES Original Filed Oct. 30, 1925 3 Sheets-Sheet 3 IIIIIII f'zuenfar CZaudsEfZZCfi Patented Oct. 8, 1929 UNITED STATES CLAUDE n. rrron, or wrnmnrrn, rumors L IAC HINE FOR H AKIN G VACUUM TUBES Original application filed October 30, 1925, Serial No. 65,774. Divided and this application filed October 17, 1927. Serial No. 226,718.

My invention relates to a machine for making certain mounting portions of vacuum tubes, incandescent light bulbs and the like.

This application is a division of my co- 5 pending application, Serial N umber-65,774, filed October 30, 1925, for vacuum tube and methodof making the same.

It is a purpose of my invention to provide a machine for making a stem unit for vacuum 10 tubes and'the like, with an exhaust passage therein, comprisingmeans for en porting a tubular'member throughwhich t e exhaust passage "extends and a tubular member of larger diameter forming the stem portion in embracing relation to the first mentioned tubular member; to provide means tor supporting a plurality of wires in predetermined spaced relation between said tubular members and to provide a core insertable within the inner tubular member cooperating with a, pair of jaws engaging the outer tubular member so as to compress said tubular members between said core and said jaws While heated to a plastic condition to firmly unite said members and seal the wires therein.

The core is preferably of such a size that thc'same expands the inner tubular member toward the outer tubular member and the;

' jaws engaging the outer tubular member are preferably curved so as to provide a pair of substantially semicylindrical faces engaging the outer tubular member While the inner tubular member is of a cylindrical form with a tapering end portion. The inner tubular member is preferably provided with a widened end that receives the core and in order to prevent the decrease in diameter of this member when heated to a plastic stategfit is sometimes desirable to insert a rotating core or mandrel within said member before the jaws engage the outer member to compress the same and unite the same with the inner tubular member. 1 It is accordingly a purpose of the inventio to provide a core member that may be projected intothe inner tubular member as the jaws are moving toward each other into compressing position and to provide means for moving ,said coreinto said inner tubular member and simultaneously rotating the ing'at'the same at right angles to Fig. 1;

same,.said movement being independent of the movement of the jaws.

It is also a purpose of the invention. to provide a core member projectable into the inner tubular member movable with the jaw members as the same move toward each other that is provided with means for limiting the movement of said core member so asto halt the same before the jaw members engage with the outer tubular member to compress the same.

As the supporting means for the tubular members rotates and the jaws and the supporting means form part of a rotating head,

the core member may either be rotated in such a manner as to rotate relatively to the other rotating parts or may be held stationary which will produce the effect of a relative .rotation between the support and the core member to thus shape the inner tubular member and hold the same from necking in during the heating operation.

Other objects and advantages of the invention will appear as the description of the accompanying drawings proceeds. However I desire to have it distinctively understood that I do not intend to limit myself to the ex act details shown or described, but that I in tend to include as part of my invention all such obvious changes and. modifications of parts as would occur to a person skilled in this art and as would fall within the scope of the claims.

In the drawings Flg. 11s a view in side elevation of my im proved machine, certain portions thereof be .ing partly broken away;

Fig. 2 is a View partly in section on the line 2-2 of Fig. 1; and partly in elevation look- Fig. 6 1s a'fragmentary view partly in section and partly in elevation of the structure shown in Fig. 5 with the parts in a different position.

In Figs. 1 to 4 inclusive, one form of the machine included in my invention is shown and in this form, a base plate or member is provided in which is journaled a verticallyextendihg hollow shaft 21 which is provided with a bevelled gear 22 engaging with the bevelled gear 23 mounted on the drive shaft 24. Mounted on the. shaft 21 is a rotatable head having a circular base portion 25 that is secured to the shaft 21 to rotatetherewith by means of a set screw 26 or an other suitable means.

Exten ing upwardly from the base member 25 is a pair of side arms 27 of a vertically extending frame member which are connected adjacent their upper ends by aweb portion 28. The upright frame members are further provided with a pair of ears 29 projecting laterally therefrom that are apertured to receive the pivot pins 30 upon which the links 31 are pivoted. Said links 31 are provided with upwardly extending arms .32

that terminate in jaws 33. The links 31 are further provided. with bifurcated portions 34 below the fingers 32 which are apertured to receive the pivot pins 35 for pivotally connecting the elongated links 36 therewith.

The links 36 are mounted so that the same diverge upwardly and are pivotally connected at 37 at their lower ends to the pivot cars 38 by means ofthe'pivot pins 37 The pivot ears 38 are provided on a yoke member 39 which is mounted on the shaft 40 exing' the wires 46, the openings being ar 1 rangedin a circular series, and the member 44 and connecting web portion 28 being provided with a longitudinal bore 47 substantially concentric with the circular series of openings 45.. Mounted within the bore 47 is a rod like mandrel or core 48 substantially cylindrical except at the extreme end portion thereof which tapers on a curve as indicated at 49 and terminates in a substantially flat end portion 50. The member 48 is secured in any suitable manner as by means of the reduced screw-threaded portion 51 with a cross bar 52 having pairs of ears 53 thereon provided with the slots 54 in which operate the "ins-55 rovided on the links 36.

As the r0 or she t 40 is moved upwardly, the yoke 39 is carried upwardly therewith moving the links 36 from the position shown in Fig. 2 to the position shown in Fig. 3.

At thesame time the cross bar 52 is carried upwardly moving the core 48 upwardly until it assumes the position shown in Fig. 3. One of the'members 27 is provided with an apertured ear 56 through which passes the vertically extending rod 57 having a sleeve 58 provided thereon, the lower end of the rod 57 having a handle member 59 provided thereon that has an enlarged sleeve-like portion' 60 embracing the rod 57 and secured thereto in any suitable manner. A coil or compression spring 61 is mounted between the car 56 and the enlargement 60. On the upper end of the rod 57 is mounted a pair of jaws 62 and 63- which cooperate-to hold the exhaust tube 64 of glass in a vertical position and in the proper position for cooperation with the otherparts that are to be unitedin the machineT' The lower end of the tube 64 is flared so as to increase the diameter thereof, as indicated at 65 before placing in the machine and rests on the upper surface 66 of the support 44. Thus, the sup port 44 acts to not only support the wires 46 in their proper relative position, but also supports the tube 64 in proper position relative thereto.

Pivotally mounted between the members 27 on the pivot pins 67 is a pair of jaws 68 which operate between the pairs of guide cars 69 extendingoutwardly from the members 27 and which are normally-pulled toward each other by means of the spring 70 secured to the pins 71 extending outwardly from the members 68. The upper ends of the members 68 have secured thereto a pair of jaw members 72 that together embrace the stem forming member '73 and are shaped to conform to the outer surface-thereof, said stem forming member being provided with I an outwardly curved flared upper end 74 that rests against the top faces ofthe jaws 72 in such a manner that the lower end 75 of the member 73 will be slightly spaced fromjthe surface 66 as is clearly shown in Figs. 1 and 2. The lower ends of the jaws 68 are provided with depending extensions 76 .thatare provided with the transverse handles 77 on the ends thereofwhich engage with the members 27 to limit the outward movement of to limitthe inward movement of the jaws 68.

The entire head comprising all the parts mounted on the members 21 and 40 rotates as a'unit and suitable stationary nozzles, such as the nozzles 83, are provided so as to provide the gas flame 84 for heating the glass members 64 and 73, the nozzles being so placed that the lower'end portions of themember 73 is heated as clearly shown in Fig. 2 by the .faces 87 opposite eachother.

flame playing thereagainst and the flame wires being elongated and acting as conduc-' tors and others being short. (preferably about one-eighth inch long),and acting as sealing means and anchoring means for the wires 46, the borated copper clad wires uniting more firmly and sealing'more thoroughly within I the glass than the wires 46. The wires 46 may be of any suitable metal having the desired rigidity to serve as supporting means for the elements of thevacuum tube. The openings are slightly larger than the wires 46 so that the same can be readily placed therein without binding. The diametersof the portion 65, of the member '64 and of the member 73 are such that there is suflicient space between the same for the wires 46, the openings 45' being so placed preferably that the wires 46 engage with the'outer surface of the portion 65 of the glass tube 64.

Referring now to Fig. 2, my improved method of making a stem for a vacuum tube,

or other glass vessel from which the air is er;- hausted, provided Withan exhaust tube is practiced by mounting the parts substantially as shown'in Fig. 8. The wires 46 are mounted with the ends thereof to which the wires 88 are securedextending a short distance between the tubcs 73 and 64 and preferably in engagement with the widened portion 65 of the tube 64. The parts are then heated uniformly at the lower end of the member 7 3 and the widened portion 65 of the member (54,18'

zone in which the parts areheated embracing substantially the entire widened portion 65 of the member 64 and the portion ot the member 73 opposite thereto. This heatlng 1s continued until the glass tubes in the heated zone thereof reach substantially a plastic state. In order to uniformly heat the parts 3 and 64, the same are preferably rotated with the flames 84 playing thereagainst as shown in Fig. 2, there being as many of said flames provided as is necessary to properly heatthe tubes. The borated wires 88 and wires 46 are, of course, also heated to a certain extent, the borated copper clad wires then being in acondition to seal readily within the glass. As a result of the heating, there is a tendency for both the members 73-hnd 65 to reduce in diameter due to the fact that the weight of the glass tends to draw the same downward. The mandrel or core 48 is made slightly larger than the internal diameter of the member and the member 65 will practically always be of smaller diameter than the core 48 after the same has been heateddue to such reduction of the diameter of the same because of being heated.- The core 48 is, however, proportion 65 outwardly and increase the diameter thereof as the core 48 is projected into the same. 1

After the members 73 and 65 have been heated to the proper extent, the mandrel or core 48 is inserted and the jaws or dies 33 are applied to the exterior thereof to thus com-' press the members 65 and 7 3 between the core 48 and the jaws 33 with the wires 46 therebe tween. The portions of the members 73 and 65 engaged by the jaws 33 and by the core 48 be ng in a plastic state, thefs'sfmewill be united into an annular joint indicated by the nuvided with a tapered noseat 49 to spread'the meral 89 which acts as an anchoring means for the wires 46, the borated copper ela'd w1res'88 being fused in and sealed in the joint 89 so that the entire joint with the Wires therein is air tight, the joint being of smaller external diameter. than the original external diameter of the tube 73- due to the compressing action of the jaws 33 and being.

of larger internal diameter than the tubular portion 65 of the member 64 due to the expanding action of the core '48. Due to the shape of the jaws, an annular shoulder 90 is formed between the portion 89 and the tubular portion 73. The wires are arranged .in an annular series, as will be evident from Fig. 4, before the compressing operation takes place and will be sealed inthe annular portion 89 in such a series as shown in Fig. 4. In Figs. 5 and 6, a slightly different form of apparatus 'for makin the stem portion is shown. Certain parts t ereof are the same 1 as shown in-Figs. 1 to 4 'inclusiveand these bear the same numerals. The principal difference between the form of the invention shownin Figs. 5 and 6 and that shown in-t-he previously described form, is that the core or mandrel that is-adapted-to enter within the 'tubular member 64 at the enlarged end 65 thereof, is rotatable relative to the support 44 and accordingly,- rotatable' relative to the tubular member 64. This aids'in shaping the portion 65 properly and preventing reduc-- tion in diameter of the same during the heat-' ing operation and also prevents the tubular member 64 from sticking to the core.

Re'ferrin to 'Fig. 5, it will be seen that the axially shi table member 40 is of greater length than the member 40 extending outwardly at the lower end of the gear 22 and extending upwardly through the member 52 corresponding to the member 52 in Figs. 1 to 4 inclusive. Said member 40' passes through an enlarged opening 107 in the member 52' and may be made integral with the core 48. Atlange 108 is provided where the member 40' joins the member 48' and a coil compression spring 109 is mounted on the member 40 between the flange 108 and the of the member 52.

washer 110 that engageswith the upper side The member 48 is made of substantially the same shape as the member 48, but instead of merely moving axially in the portion 44, it is rotatable relative thereto either by holding the same against rotation as the head rotates, or by rotating the same by any suitable means at a different rate than the rotation of the head. \Vhile the member 40' is adapted to be raised when the member 52' is raised as the jaws 33 move toward each other, the same is also adapted to be independently raised and rotated.

Any suitable means may be provided for this purpose, one form of such means being shown diagrammatically of Fig. 5, the member 40 being provided with a disk 111 mounted so as to rotate therewith with which the friction wheel 112 is adapted to engage, said friction wheel being mounted on a shaft 113 which is rotated by means of a shaft 114.

with which it is connected by the universal joint 115, which shaft 114 is driven from 1 the same source of'power as the shaft 24 if desired. A sleeve 116 is provided on the shaft 113 and is adapted to be raised and lowered by the rod 117 which is connected with apivoted yoke 118 on the sleeve 115, said rod 117 being operatedby any suitable handle or pedal as desired.

It will be seen that when the friction wheel 112 is moved into engagement with the disk .111, rotation of the member 40 will result and as the same is lifted further, due to endesirable that the member 48 shall have completed its movement before the jaws 33 engage with the tubular member 7 3. The flange 108 enters a socket portion 119 in the member 28 and as the member 52. moves up,- wardly, the parts 40', 48' 'and108 will move therewith as well as the spring 109. However, when the flange 108 engages with the wall 120 of the socket 119, the movement of the member 48' upwardly will be halted after which the spring 109-wil1 be compressed as the jaws move into engagement with the member 7 3 whereby the movement of the member 48 is completed before the jaws 33 reach their linalcompressing position. Fig. 6 shows the position of the jaws 33 when the flange member 108 engages with the wall 120. From the point shown in Fig. 6 in full lines on until the dotted position-is reached, the

.member 73 as described above.

jaws 33 move while the member 48' is stationary.

The shaft 21' extends upwardly from the member 22 in a similar manner to that in which the shaft 21 extends upwardly from the member 22 in the form shown in Figs. 1 to 4 inclusive, but is of greater length and is threaded at the end 122 thereof to receive the nuts 43', the end portion 122 being of reduceddiameter to provide a shoulder 121 between which and the nut 43, the member 39 is clamped.

In operating the machine shown in Figs. 5 and 6, the member 48' is preferably projected into and rotated within the .I QI 1 1ber 65 by operation of the operating rod 117, before the jaws 33 are closed, the member 48' being again carried upwardly but without rotation relative to the tubular member-64 and the supporting member 44 when the aws 33 are'moved toward, their compressing position, the member 48 completing its movement before the jaws 33 engage with the lVhile the member 48 is shown as being rotated by the engagement of the wheel 112 with the disk 111, obviously a similar result can be obtained by holding the member 48' from rotation and raising the same. As the member 44 and the members 7 3 and 64 are all rotating together, with the head of the machine, the holding of the member 48 from rotation and raising the same will produce the same result of shaping and spreading the tubular portion 65 when stationary as when the same is rotated at a different speed or in a different direction than the head, as all that is necessary is to have relativerotation of the member 48 to the tubular member 65. While it is not absolutely necessary to rotate the core and while there would not be any great reduction in diameter of the member 65 if the wires 46 are in engagement therewith, yet when these do not engage with the tubular portion 65, the member 48 is preferably rotatable to more etliciently shape the ortion 65 and increase the diameter thereo while the same is in a plastic state.

I'llaving thus described my invention what I desire to claim and secure by United States Letters Patent is:

1. In a machine of the character described, a support having wire receiving openings therein, a core projectable through said support, a pair of jaws, movable toward and away. from said core above said support, means for moving said jaws toward each other and means for projecting said core from said support and rotating the to said support.

2. In a machine of the character described, a support having wire receiving openings therein, a core proje'ctable through said sup port, a pair of jaws movable toward and away from said core above said support,

same relative means for moving said jaws toward each other and simultaneously projecting said core from said support and means for projecting said core from said support and rotatmg the same relative to said support.

3. In a machine of the character described,

' a support having wire receivingopenings therein, a core projectable through said sup- 

